As Trrunde already said, it will work perfectly with pfsense, I have used it together with HET-3012 for some time now. The level of knowledge at these customer service centers scares me, they are really clueless sometimes.

Reminds me of the installation technician who installed the HET-3012. He claimed the exact same thing, but got a pretty long face when I connected the pfsense box and binned the Zyxel as he stood and watched.